These four megalithic sites are the most dense concentration in the zone and have Outstanding Universal Value, representing a traditional monumental megalithic construction spread out over a vast area, with more than 1,000 stone circles scattered along one of the major rivers of Africa. The work established that the single burials appeared to precede in time the multiple burials associated with the stone circles. The most recent excavations conducted on these megalithic circles date to the Anglo-Gambian campaign led by Evans and Ozanne in 1964 and 1965. Criterion (i): Individual stones finely carved bear witness to an exact and experienced technique and contribute to the organized and imposing size of the stone circle groups. The stone circles stand in a farmed landscape and there have been few interventions.